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September/October 2011
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Post-Tensioning Tendon Grout

Post-tensioning strand being inserted into preformed ducts embedded in the concrete. The duct will typically taper to where the duct area is approximately two to three times the steel area.

A new ASTM International standard, adopted from an American Concrete Institute test method, will be used to help ensure the safety of construction projects.

ASTM C1741, Test Method for Bleed Stability of Cementitious Post-Tensioning Tendon Grout, is under the jurisdiction of Subcommittee C09.41 on Hydraulic Cement Grouts, part of ASTM International Committee C09 on Concrete and Concrete Aggregates. C1741 shares its title with and is based on the American Concrete Institute’s ACI 423.9M-10.

“Bleeding of post-tensioning grout creates pockets of reduced corrosion protection in the tendon,” says Fred Goodwin, fellow scientist, BASF Construction Chemicals LLC, and an ASTM member. “The primary purpose of grouting the tendons is to provide corrosion protection. Corroded post-tensioning tendons can lead to catastrophic failure.”

Goodwin notes that being able to predict bleeding in the grout before injecting into the tendon will maximize grout performance for bleeding resistance, leading to safer and more reliable construction practices.

Material manufacturers, grouting contractors, specifiers, state departments of transportation and testing laboratories will be the primary users of C1741.

All interested parties are encouraged to take part in the standards developing activities of C09.41. Those interested in participating in the upcoming interlaboratory study for C1741 are encouraged to contact the subcommittee.

CONTACT

Technical Information: Fred Goodwin, BASF Construction Chemicals LLC, Cleveland, Ohio

Phone: 216-839-7009

ASTM Staff: Scott Orthey

Phone: 610-832-9730